1. Field of the Invention
The present invention relates to portable communication systems, and more particularly, to a system and method for providing a seamless roaming solution to a portable client device to decrease communication cost and improve communication performance.
2. Description of Related Art
It is very advantageous to permit individual workstations, personal computers and other devices to communicate together over a network. The network enables each client node (i.e., individual computing device) to access data and other devices, such as laser printers. A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link and typically share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users (i.e., clients). A local area network may serve as few as two or three clients (for example, in a home network) or as many as thousands of clients (for example, in an FDDI network). Ethernet is the most commonly used LAN technology, but other networking technologies such as Token Ring, FDDI, and ARCNET are also used in some applications.
There is a growing desire to have network clients be portable or to have a portable communication client that can operate beyond a defined environment. A portable communication client is particularly useful for remote data collection applications such as inventory control, manufacturing and production flow management, and asset tracking. For example, a mobile worker may move throughout a work area carrying the portable communication client and then send and receive inventory control, manufacturing and production flow management, and asset tracking status and updates to and from the server. The mobile worker may also exit the immediate work area and travel over a wide geographic area. It is very desirable that the mobile worker maintain network connectivity as it moves throughout the travel range.
To address this need for portability, many businesses have adopted wireless local area networks (WLANs) based on the IEEE 802.11 standard that allow mobile users to connect to their wired LAN via a wireless radio connection. To deploy a wireless network, client devices such as desktop computers, laptop computers and personal digital assistants are equipped with wireless network cards. A wireless access point connects to the regular wired office backbone and then communicates with wireless network cards installed in the client devices via radio signals, thereby connecting the two. A wireless wide area network (Wireless WAN or WWAN) covers a much more extensive area than WLANs. Coverage is generally offered on a metropolitan, national or even global level (IEEE 802.16, 802.20) with wireless network infrastructure provided by a wireless service carrier (for a monthly usage fee, similar to a cellular phone subscription). While WLANs are used to allow network users to be mobile within a small fixed area, WWANs can provide connectivity over a much broader coverage area, for mobile users such as business travelers or field service technicians. WWANs allow users to have access to the Internet, e-mail, and corporate applications and information while away from their office. WWANs use licensed and unlicensed frequencies for data and voice transmission.
Each of these types of networks has distinct advantages and disadvantages. Generally, WLAN services offer high-bandwidth connectivity but limited coverage, whereas WWAN service typically offers better coverage but lower bandwidth. There are cost differences as well between these networks, and it is usually less expensive to connect through a WLAN than through a WWAN. With the advent of public access 802.11 network areas, often called hotspots, it is desirable to leverage these available WWAN, WLAN and/or LAN resources to provide a faster, more efficient and lower cost method of connecting the client to its server.
Accordingly, it would be desirable to provide a system and method that enables a portable communication client to easily switch or roam from one type of communication network to another depending upon availability and/or cost.